Solid phase conditioning

Abstract

The present invention relates to a method for conditioning reversed phase SPE cartridges that provides certain advantages compared with known such methods. The method of the invention finds particular use in the automated synthesis of radiolabeled compounds where SPE is used for example in the purification steps.

The invention claimed is: 
     
       1. A method to condition a tC18 reversed phase solid phase extraction (SPE) cartridge in an automated synthesizer cassette prior to trapping  18 F-FTAG on the SPE cartridge, wherein said method comprises the sequential steps of passing through said SPE cartridge:
 (i) an inorganic solvent, wherein said inorganic solvent comprises NaOH; 
 (ii) a polar organic solvent, wherein the polar solvent comprises ethanol; and 
 (iii) a low-strength solvent, wherein the low-strength solvent comprises aqueous ethanol; 
 wherein steps (i)-(iii) occur at 35° C., the  18 F-FTAG is trapped on the SPE cartridge at 35° C., and 
 the uncorrected for decay end of synthesis (EOS) yield of  18 F-FDG is at least 77%. 
 
     
     
       2. The method as defined in  claim 1  wherein said conditioning further comprises the following step (iv) of passing a low-strength solvent through said SPE cartridge wherein said low-strength solvent is selected from water or a buffer. 
     
     
       3. The method as defined in  claim 1  wherein between 0.2-2.0 mL of said inorganic solvent is passed through said SPE cartridge in said conditioning step. 
     
     
       4. The method as defined in  claim 1  wherein said method further comprised purification of a reaction mixture through the SPE cartridge to obtain the  18 F-FDG in a purified form. 
     
     
       5. The method as defined in  claim 1 , wherein the SPE cartridge is flushed with nitrogen before step (ii) to remove residual inorganic solvent.